Locking electrical connector



Oct. 31, 1967 J. MISENCIK ETAL 3,350,675

LOCKING ELECTRICAL CONNECTOR Filed Oct. 11, 1965 2 Sheets-Sheet 1 FIG.3

INVE NTORS ATTORN EY5 United States Patent Ofifice ABSTRACT OF THE DISCLOSURE The instant device is a plug and socket connector having a latching means comprising a slotted prong having an enlarged opening at the inner end of the slot, the

prong being disposed on the plug and in the socket, a headed member receivable in the enlarged opening of the prong and mounted on the outer end of a solenoid armature by a shank portion receivable in the slot of the prong. The armature moves laterally with respect to the prong and is spring biased to the outer position. A mechanical operator, normally spring biased outwardly and having a path of movement parallel to the slotted prong,

is provided with a notch which receives the headed member in the inner position of the operator and the outer position of the headed member. This corresponds to the latching or unlatching position. The normal position of the mechanical operator, being outward, holds the headed member in a position to block latching or unlatching. The solenoid is in series with a switch and the two are connected between the opposite poles of the power terminals of the socket. A switch operator mounted on the mechanical operator is spaced from the switch in the outer position of 'said mechanical operator, whereby the solenoid is normally deenergized. When the socket terminals are deenergized, the mechanical operator, when pushed inwardly, closes the switch but to no purpose and vthe spring biased solenoid drives the headed member outwardly to. permit latching or unlatching. When the socket terminals are energized, pushing the mechanical operator inward closes the switch in series with the solenoidjand the latter prevents outward movement of the headed member, to thus block latching or unlatching.

This invention relates to a locking electrical connector and, more particularly, to a connector of the type having a separable body and plug.

In electrical cable connectors designed to supply relatively high power loads, it is important that suitable provisions be'made to prevent the connectors from being engaged or disengaged while energized. This is because of the arcing which occurs when making and breaking sucha circuit and the risk of injury both to equipment and to personnel'which is apt to result from such arcing.

'Varioustypes of mechanical and electrical locks have been proposed for use with cable connectors to prevent their engagement or disengagement while energized. One

type of locking arrangement which has proved successful is disclosed in UnitedStates Patent No. 3,131,012, which patent construction is that the solenoid remains energized at all times during which the connector body is ener- 3,350,675 Patented Oct. 31, 1967 gized. Thus, the solenoid must be designed and engineered for continuous operation. It would be desirable to provide a connector having the same operating characteristics as that of the patented device, but wherein the solenoid would not be continuously energized.

Accordingly, it is a primary object of the present in vention to provide an improved electrical connector having a safety locking means. Other objects are to provide such a connector wherein the locking means includes a solenoid which is normally deenergized, and to provide a connector which is reliable and safe.

The manner in which the foregoing objects are achieved will be more apparent from the following description, the appended claims and the figures of the attached drawings, wherein:

FIG. 1 is a perspective view of a separated connector body and plug in accordance with this invention, a portion of the plug being broken away to illustrate its construction;

FIG. 2 is a partial cross sectional view of the connector body and plug of FIG. 1 in their mated position;

FIG. 3 is a partial view of the connector body of FIG. 2, showing the mechanism in a different stage of operation;

FIG. 4 is a perspective detail view illustrating the locking operation; and

FIGS. 5-10 are partially schematic illustrations of various operating stages of the invention.

The objects of the invention are achieved by means of an electrical connector wherein the connector body includes a plurality of contacts connectable to a power supply. Solenoid means is provided on the connector body and is connected for energization from the power supply. The connector body also includes normally open switch means which are in series with the solenoid. The solenoid includes a core which is movable between a solenoid energized position and a solenoid deenergized position. The core, while in its energized position, is arranged to prevent engagement and disengagement of the connector body with a mating connector plug. A spring normally biases the core to its deenergized position, The connector body additionally includes latching means which normally retains the core in its energized position, but is manually operable to release the core and close the switch.

With particular reference to FIG. 1, there is illustrated a connector including a connector body 10 and a connector plug 12. The plug 12 includes an insulating base 14 from which project the usual line blades 16, 18 and a grounding blade 20. These blades are connected in the usual manner by wiring means (not shown) to the conductors of a cable 22 supplying the load. In addition to the line and grounding blades there is provided a locking blade 24. The locking blade is longer than the electrical contact blades and is bifurcated at its outer end, as shown more clearly in FIG. 4, to form a narrow slot 26 terminating in a round aperture 28 having a diameter greater than the width of the slot 26. The plug 12 further includes an outer steel housing 30 which extends beyond the contact blades to form a skirt 32.

The connector body 10 includes a steel housing 34 within which is mounted a generally disc-shaped base member 36 constructed of insulating material. A central insulating member 38 is positioned adjacent the base member 36. An insulating cap member 40 is positioned against the central member 38 and the central member and cap are enclosed within an insulating shell 42. Shell 42 is generally cup-shaped to provide a forward face 44 which defines openings 46 for receiving the contact blades 16, 18, 20 of the connector plug and an opening 48 for receiving the locking blade 24. The entire connector body assembly is secured together by means of 3 screws 50 which extend from the forward face 44, through the assembly into the tapped openings in the rear wall of the housing 34. The forward end 52 of housing 34 is flared outwardly as shown to provide an annular recess for receiving the skirt 32 of the connector plug 12 when mated therewith.

It will be noted from FIG. 2 that the central member 38 of the connector body is substantially hollow so as to form a switch chamber 54 therein. In addition, the mating ends of the central member 38 and the cap member 40 are inletted so as to retain a solenoid 56 therebetween. The solenoid is positioned so that its magnetic core 58 is radially vertically movable as viewed in FIG. 2. The cap member 40 defines a radial passage 60 into which the lower end of the core may extend and passage 60 communicates with a longitudinal guideway 62 within which is mounted a latching plunger 64 which includes a shoulder 65 and a small diameter end which extends through a passage 37 in base member 36 and through the rear wall of housing 34 to form a release button 66. Outward motion of latching plunger 64 is limited by a recess 39 which is positioned to receive shoulder 65. The cap member 40 and the central member 38 also define a guideway aligned with opening 48 for receiving a locking blade 24. The inner surface of the shell 42 is cut away to form three peripherally displaced contact housing chambers 68 which enclose the usual female contacts 70 for receiving the line and grounding blades of the plug. As this portion of the construction is conventional, only one of the contacts 70 is illustrated. Each contact includes suitable wiring means, such as the screw connector 72, for securing one of the conductors 74 of an electrical power supply cable 76.

The solenoid 56 includes a lead 78 which is connected to the same screw connector 72 as the conductor 74. The other lead 80 is connected to the fixed pole 82 of an electrical switch 84 which is mounted within the switch chamber 54. Another lead 86 extends from the movable pole 88 of the switch to one of the other screw connectors 72 (not shown) to which a line conductor of the power supply cable 76 is secured. It will be noted that the movable pole 88 is positioned adjacent the nylon latching plunger 64 and that a switch actuating lug 90 on the latching plunger is positioned to engage the pole 88 and close the switch when the release button 66 is in its depressed position, as illustrated in FIG. 2. Latching plunger 64 also defines a depression 67 for receiving the end of core 58. The latching plunger 64 is normally biased outwardly, as indicated by FIG. 3 and the dotted line of FIG. 2, by means of a spring 92 housed in the end of guideway 62. In addition, it will be noted that the solenoid core 58 is normally urged outward from the solenoid 56 by means of a spring 94 mounted within the solenoid coil. It is important to note that the outer end of the solenoid core 58 includes a narrow pin portion 96 which terminates in an enlarged rounded head 98. The diameter of pin 96 is sufiiciently small that it will easily pass through the slot 26 in locking blade 24 and the enlarged head 98 is small enough to pass easily through the aperture 28 in the locking blade but is too large to pass through the slot.

Operation The normal deenergized arrangement of the movable parts of the body is illustrated in FIG. 3. The spring 92 maintains the latching plunger 64 in its outwardmost position. The spring 94 Within the solenoid 56 causes the head 98 of the solenoid core to rest against the latching plunger. Under these circumstances, the head 98 is positioned in alignment with the opening which would normally admit locking blade 24. As head 98 is larger than slot 26 on the locking blade, the connector plug 12 cannot be mated with the connector body 10.

Assuming that the power supply cable 76 is deenergized, the parts are mated by depressing the release button 66 4 as illustrated in FIG. 2. This causes the depression 67 to be displaced axially toward the left, allowing the spring 94 to move the head 98 downwardly into the depression and out of alignment with the opening for locking blade 24. The locking blade may then be inserted, as shown in FIG. 4, allowing the plug 12 to be mated with the body 10.

When mating is complete, as shown in FIG. 2, the button 66 may be released. This causes the depression 67 on latching plunger 64 to be returned to its original position, camming the head 98 upwardly into the aperture 28 of the locking blade. The plug 12 cannot thereafter be removed without depressing the button 66.

It will be noted that the switch 84 is normally open until the release button 66 is depressed, causing the movable pole 88 to contact the fixed pole 82. The significance of this can be best understood by reference to FIGS. 5 and 6. Assume that the power supply cable is energized, and the body and plug are connected. This condition is illustrated in FIG. 6, wherein it will be noted that head 98 is held in the locking position relative to locking blade 24 by latching plunger 64. It will also be noted that switch 84 is opened so that the solenoid is deenergized. If disengagement of the plug from the body is attempted by depressing the button 66 to force the latching plunger 64 to the left, as viewed in FIG. 5, the lug forces the movable pole 88 of switch 84 against the fixed pole 82, thereby closing the switch and energizing the solenoid. The solenoid then retains the head 98 in its raised position so that the plug cannot be separated from the body.

A similar condition will exist if the connector plug and body are initially separated and if an attempt is made to mate them while the power cable is energized. This is illustrated in FIGS. 7 and 8. In FIG. 7, it will be noted that the enlarged head 98 of the solenoid core is in line with the locking blade 24 so that the plug is unable to enter the connector body. Depression of the latching plunger 64, as shown in FIG. 8, closes the switch 84 thus energizing the solenoid and retaining the enlarged head 98 in the same position.

An alternative arrangement which operates in a somewhat dififerent fashion is illustrated in FIGS. 9 and 10. In this arrangement, a modified latching plunger 100 is employed wherein the depression 102 is formed with a relatively sharp edge 104 at its forwardmost end. The advantage of this construction is that the enlarged head 98 of the spring-loaded solenoid core 58 serves as a mechanical latch whenever the solenoid is deenergized. As the edge 104 is unable to cam the head 98 upwards, it serves to retain the plunger 100 in its forwardmost osition. Thus, the locking blade 24 is allowed to enter without requiring that the button be depressed for each mating. However, as soon as the solenoid is energized, the head 98 is retracted as shown in FIG. 10, allowing the plunger 100 to return to its normal latching position. It will thus be seen that the illustrated invention achieves the objectives hereinbefore set forth by reventing either engagement or disengagement of an electrical connector while the power supply cable is energized. Furthermore, this result is achieved without requiring that the solenoid remain energized. The solenoid, under these conditions, is energized only when the manual release button is depressed.

It is believed that the many advantages of this invention will be immediately apparent to those skilled in the art. It will also be understood that a number of variations and modifications may be made in this invention without departing from its spirit and scope. Accordingly, the foregoing description is to be construed as illustrative only, rather than limiting. This invention is limited only by the scope of the following claims.

What we claim as new and desire to secure by Letters Patent of the United States is:

1. In an electrical connector body including a plurality 'of electrical contacts connectable to a power supply, the

improvement which comprises: solenoid coil means connected for energization from said power supply; normally open switch means in series with said solenoid coil means; a solenoid core movable between a solenoid-energized position and solenoid-deenergized position, said core in its energized position being arranged to prevent engagement and disengagement of said connector body with a mating connector plug; spring means normally biasing said core to its deenergized position; and latching means on said body normally retaining said core in its energized position but manually operable to release said core and close said switch means.

2. The improvement of claim 1 wherein said body defines a longitudinal passage for receiving a bifurcated locking blade having a longitudinally extending slot terminating in an aperture of a transverse diameter greater than the width of said slot and wherein said core comprises: a pin portion slidably engageable by said slot when said core is in its deenergized position; and an enlarged head portion engageable with said aperture when said core is in its energized position.

3. The improvement of claim 1 wherein said latching means comprises: a latching plunger axially slidable in said body between a first and a second position along a path transverse to the motion of said core, a first portion of said plunger being adapted to retain said core when in said first position, and a second portion of said plunger being adapted to release said core when in said second position; biasing means normally urging said plunger to its first position; a release button portion of said plunger positioned externally of said body and depressible to move said plunger to its second position; and switch actuating means on said plunger operable to close said switch means upon movement of said plunger to said second position.

4. The improvement of claim 3 wherein said switch means comprises a fixed contact and a movable contact and wherein said switch actuating means comprises a lug on said plunger engageable with said movable contact.

5. The improvement of claim 3 wherein said second portion ofsaid plunger defines a depression for receiving the end of said core therein.

6. In a longitudinally extending electrical connector body including a plurality of electrical contacts connectable to a power supply cable, and defining a plurality of contact blade receiving passages and a locking blade receiving passage, the improvement which comprises: solenoid coil means connected for energization from said power supply cable; a solenoid core transversely movable relative to said body between a solenoid-energized position and a solenoid-deenergized position, a free end of said core extending from said coil means and including a pin portion terminating in an enlarged head, said head being aligned with said locking blade receiving passage when said core is in its solenoid-energized position, and said pin portion being aligned with said locking blade receiving passage when said core is in its solenoid-deenergized position; normally Open switch means in series with said solenoid coil means; spring means normally biasing said core to its deenergized position; a latching plunger axially slidable in said body between a first and a second position along a path transverse to the motion of said core, a first portion of said plunger being adapted to retain said core in its energized position when in said first position, and a depressed portion of said plunger being adapted to release said core when in said second position; biasing means normally urging said plunger to its first position; a release button portion of said plunger positioned externally of said body and depressible to move said plunger to its second position; and switch actuating means on said plunger operable to close said switch means upon movement of said plunger to said second position.

7. The improvement of claim 6 wherein said switch means comprises a fixed and a movable contact and wherein said switch actuating means comprises a lug on said plunger engageable with said movable contact.

8. The improvement of claim 6 wherein said depressed portion includes a latching edge engageable with said head to retain said plunger in its second position when said head is seated therein.

References Cited UNITED STATES PATENTS 2,298,313 10/1942 Ross 339-12 X 2,735,992 2/1956 Bailey 339-84 X 3,131,012 4/1964 Healy 339-12 MARVIN A. CHAMPION, Primary Examiner. PATRICK A. CLIFFORD, Assistant Examiner. 

1. IN A ELECTRICAL CONNECTOR BODY INCLUDING A PLURALITY OF ELECTRICAL CONTACTS CONNECTABLE TO A POWER SUPPLY, THE IMPROVEMENT WHICH COMPRISES: SOLENOID COIL MEANS CONNECTED FOR ENERGIZATION FROM SAID POWER SUPPLY; NORMALLY OPEN SWITCH MEANS IN SERIES WITH SAID SOLENOID COIL MEANS; A SOLENOID CORE MOVABLE BETWEEN A SOLENOID-ENERGIZED POSITION AND SOLENOID-DEENERGIZED POSITION, SAID CORE IN ITS ENERGIZED POSITION BEING ARRANGED TO PREVENT ENGAGEMENT AND DISENGAGEMENT OF SAID CONNECTOR BODY WITH A MATING CONNECTOR PLUG; SPRING MEANS NORMALLY BIASING SAID CORE TO ITS DEENERGIZED POSITION; AND LATCHING MEANS ON SAID BODY NORMALLY RETAINING SAID CORE IN ITS ENERGIZED POSITION BUT MANUALLY OPERABLE TO RELEASE SAID CORE AND CLOSE SAID SWITCH MEANS. 